2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Ehab El-Salakawy, University of Manitoba
The use of fiber-reinforced polymer (FRP) reinforcement has emerged as a viable solution to steel corrosion in reinforced concrete (RC) structures. However, to enhance the short-term structural performance such as the energy absorbing capacity, deformation capability, and load bearing capacity after cracking the development of discrete, randomly distributed fibers cementitious mixes is required. A relatively new type of basalt fiber (BF) pellets, which is made of basalt fibers encapsulated by polyamide resin, have been recently introduced. It is characterised by high tensile strength and non-corrodible nature that is contrary to the case of steel fibers that corrode in harsh environments. For RC structures, the quality of bond between concrete and reinforcement is considered a crucial parameter so that stresses are transferred efficiently from concrete to reinforcement. In addition, the provisions for reinforcement anchorage, particularly FRP, introduce detailing problems due to the required development length. Accordingly, FRP bars are produced with a headed end to shorten the required development length, develop the bar’s high tensile capacity, and overcome all the problems associated with using FRP bars with different types of surface textures or/and bent FRP bars. The purpose of this study is to assess the bond strength of headed-end GFRP bars embedded in fiber reinforced cementitious composite mix (FRCC) via conducting pull out tests on concrete prisms. A total of 24 concrete prisms were cast using two different types of cementitious composites; normal strength cementitious composites (NSCC) and FRCC. The test parameters also included the type of fiber (basalt fibers pellets and steel fibers) and the type of GFRP bar end anchorage (straight- and headed-end bars). The pullout tests were conducted according to the guidelines of the Canadian code for FRP-RC structures. Analysis of test results pinpoints that the FRCC, reinforced with either basalt fiber pellets or steel fibers, had a superior bond to both straight and headed end GFRP bars compared to NSCC.